This study is the first comprehensive treatment of the way Marsilius of Padua (1270/1290-1342), a seminal political thinker of the Late Middle Ages, elaborated on Aristotle's political thought in articulating his political theory. Its main thesis is that Marsilius is committed to the view of a sharp disjunction between ethics and politics, thus deviating radically not only from Aristotle, but also from the majority of medieval Commentators of Aristotle such as Thomas Aquinas, Giles of Rome, Peter of Auvergne and John of Jandun. From a methodological viewpoint, it follows the model of...